Rotary core bit



Feb. 9, 1937. L. s. coPELlN ROTARY CORE BIT Filed March 4, 1935 2Sheets-Sheet l INVENTOR. L. 5. Cope/in ATTORNEY.

Feb. 9, 1937. L, 5. CQPELlN 2,070,001

ROTARY CORE BIT Filed March 4, 1935 2 Sheets-Sheet 2 IVENTOR. l 5.ope/fn mfg/oem ATTORNEY.

Patented Feb. 9, 1937 UNITED STATES FATENT OFFICE ROTARY CORE BITLeonard S. Copelin, Los Angeles, Calif. Application March 4, 1935,Serial No. 9,158

7 Claims.

This invention relates generally to rotary drills such as are employedfor earth-boring operations. More particularly it relates to theconstruction of cutting heads or bits for drills of the core-formingtype.

It is an object of the invention to provide a drill bit which willafford efficient and reliable operation and which will not tend tobinditself within the hole being drilled.

It is a further object of the invention to provide a bit characterizedby utmost simplicity of con struction and by the absence of conventionalpilot teeth surrounding the core passage.

Further objects of the invention will appear from the followingdescription in which the preferred embodiment of the invention has beenset forth in detail in conjunction with the accompanying drawings.

Referring to the drawings:

Fig. 1 is a side elevational view, in cross-section, showing a rotarycore drill incorporating the present invention.

Fig. 2 is a side elevational view, showing the cutting head or bitincorporated in the drill of Fig. 1.

Fig. 3 is a view similar bit rotated through 90.

Fig. 4 is a cross-sectional detail taken along the line 4-4 of Fig. l.

Fig. 5 is a cross-sectional detail taken along the line 5--5 of Fig. 1.

Fig. 6 is a bottom plan view of the drill shown in Fig. 1.

The drill as illustrated in Fig. 1 consists generto Fig. 2, but with theally of a drill body I0, having a cutting head or drill bit Il securedto the lower end of the same, as by means of a threaded connection I2.The outer core barrel I3 is secured to the upper end of the drill body.Within the outer barrel I3 there is an inner core'barrel or retainer I4,the lower end of which is secured to the drill body The cutting head isprovided with a vertical opening I5 concentric with the axis ofrotation, which permits a core to progress upwardly into the coreretainer I4.

r cones, indicated at 2|, represents the regio-n of (Cl. Z55-72)demarcation between the different angles to which the surfaces I8 and I9are beveled. At the lower end of the bit body there is a lip 22surrounding the core opening I6, and this lip is substantiallyuninterrupted except for portions of the wing teeth, instead of beingprovided with pilot teeth as in conventional constructions.

It is desirable from the standpoint of simplicity to form the wing teethintegral with the body of the bit, although suitable detachablemountings can be provided if desired. The wing teeth Ia, may beduplicates, and are carried on opposite sides of the bit. Each of theseteeth affords an advancing face 23 in a general plane inclined withrespect to the vertical. Below the region oi' the surface area I9 andthe lip 22, each wing tooth I8a provides a depending tooth portion 24.Thus each of the wing teeth lila is formed to afford lower substantiallyhorizontal cutting edges 2B and 21, which are stepped to cut on areas ofdifferent diameters. In Fig. 1 these areas have been designated bynumerals 28 and 29. The inner edges of tooth portions 24 extend slightlyinwardly of the periphery of opening I6, in order to form a core 32 ofproper diameter to pass upwardly into` the core retainer. The advancingface of each tooth portion 24 is shown as being a continuation of thegeneral advancing face 23 for the corresponding wing tooth.

The wing teeth I8b differ in positioning and proportioning in order toaflord a desired reaming action. Each of these teeth has an advancingface 33, which lies generally in a vertical plane. Lower depending toothportions 34 are provided, corresponding to the tooth portions 24 forwing teeth lita. Lower stepped cutting edges 35 and 3'I are provided,which likewise act on areas of the formation at different diameters.Outer vertical rearning edges 38 are provided, which extend to radiibeyond the corresponding outer edges 39 for the teeth I8a.

With respect to the positioning of the lower cutting edges 26 and 36,all of these edges preferably lie in a common plane normal to the axisof rotation. However, the lower edges 31 lie generally in a plane normalto the axis of rotation, which is at a slightly higher elevation than acorresponding plane coincident with the cutting edges 21 for wing teethI8a. In general, the advancing faces of all the wing teeth arepreferably at an angle, with respect to radii coincident to the same andnormal to the axes of rotation. In other words, the advancing faces aredisposed non-radially, so as to tend to urge cuttings outwardly as thebit rotates.` ISIS` In combination with the features described above,provision is made for delivering lubricating mud tothe bit, in suchamanner as to insure propercarrying away of cuttings without clogging.Thus the body of the bit is provided with substantially verticalpassages 4| for lubricating mud, there being one passage for each of themain teeth, It is desirable to have these passages fiattenedincross-section, as illustrated `in Fig.V 6, in order to avoid undueerosion of metal by the scouring action of sand. In this connection itmay be explained that with acircular passage for .the V'outer and lowerareas of Vthese advancing faces, asis evidenced in Fig. l.. Likewise,the discharge is immediately above the junction 2| between the surfaceareas I8 and I9. YWith respect to the formationbeing acted upon, the'disdrill bodyV 0.

charge ends ofthe ports 4| are likewise substantially directly above theshoulder 43 formed at the junction between the areas 28`and 29. As

v Y. will be presently explained, such an arrangement Yfor the portsr4|is conducive to eiicient action of the rotary mud in carrying preventingclogging. Y Y

As representative Vof a suitable expedient for away cuttings anddelivering rotary mud to the ports 4|,Vthe upperend ofthe bit body is.shown `provided with an of the ports 4| and which in turn communicateswith a greaternumberof ports 46 formed in the tice, lubricating mud iscirculated downwardlyV throughthe space-4`| between the inner and outercore barrels, to be'delivered through passages 46,

and from thence through the ports 4|.

t is generally desirable to incorporate suitable core catching means inconjunction with the drillV bit. Such a core catcher has been indicatedgenerally at 48.V

Operation of the invention described above can now be explained asfollows:-During a drilling operation, the lower tooth portions 24 and34cut on the area 28 of the formation, and therefore define the core 32`in'addition to performing a Y substantial part of the drillingoperation. Cut'-VV ting edges 2'1k of the teethV |8a (which have theVinclined advancing faces 23) cut upon the 'larger diameter area 2...-Wing teeth` |8b, and particularly the'vertical edges 38,V perform areaming` operation upon the side walls of the hole, and,

Y because of the vertical positioning of the same as distinguished fromthe inclination of the corresponding edges39 of teeth |8a, the hole isformed c5y cork-screw effect such as is common in bits of the withsmoothside surfaces, without a so-called prior art. vBecause of the Yabsenceofthe usual pilot teeth on the lip 22, more bearing pressure is madeYpossible upon the lower cutting edges, with the result that an increaseinthe rateV of drilling-is made possible.Y Likewise elimination of pilotteeth greatlyreduces frictional heat on the core, and thereforethe core`does not tend to V' ,..dry'with` consequent stickingy tothe throat orYplugging of the bit. Asl indicated in a vgeneral annular recess 44,which communicates with allV way by the arrows in Fig. 1, lubricatingmud dis- Y charged from the ports 4| is distributed over the advancingfacesof the wing teeth, with an affective flow of a substantial part ofthe mud down into the regions in advance of the lower tooth portions 24and 26. carried away from all of the active cutting and reaming edges,`to facilitate a rapid cutting rate and to prevent clogging or balling upof material about the teeth. Due to the efficient and-effectivek mannerinV which lubricating mud is circulated to the bit, and

due also to the efficient reaming action afforded by the verticalYedges38, the drill is not subject to jamming in the hole and can alwaysbe raised without diiculty.

1t is to be understood that the various cutting Vand reaming edges canbe reinforced by suitable hard metalY alloy, in order to afford greaterresistance to wear. Such practice, however, is common in the manufactureandrepair Vof rotary bits, and need not be described in detail.

'l claim: Y Y 1.5In a rotary earth-boring drill, a cutting headcomprising a body providedwith at least four circumferentially spacedteeth, two of the teeth` Thus, cuttings are effectively v on oppositesides of the head having advancing Y. faces inclined with respect to thevertical and 2. In a rotaryearth-boring drill, a cutting head comprisinga body provided with at least four circumferentially spaced teeth, twoof the teeth bey ing disposed-on opposite sides of the head and havingadvancingrfaces inclined with respect n Y, to the vertical, said teethlikewise having stepped According kto conventional praclower cuttingedges, therother teeth beingV interposed with respectjto the first-namedteeth and having substantiallyV Yvertical ladvancing faces,

cumferentially spaced teeth, two of the teeth being disposed onVoppositesides of the head and having advancing faces inclined withrespect to the vertical, said teeth also'having at leastjtwoY steppedlower-,cutting edges, the other teeth being interposed with respect'toVthe first-named teeth and having substantially vertical advancingfaces,V said last-named teeth likewise having at least two stepped lowercutting edges and to Y extending to adiameter beyond the outer diamyeterof the rst-namedfteeth'the lowermost cutting edges of all the teethbeing substantially` coincident withY respect to a common plane normalto the'axis of rotation of thedrill, the uppermost lower cuttingv edgesof the first-named teethbeing at a lower elevation than the uppermostlower cutting Yedges of the second-named Y teeth. Y

4. In a rotary earth-boring'drill, a cutting head comprisingV a.Vbody`provided with atleast four circumferentially spaced teeth, two ofthe teeth on opposite sides of the head having advancing kfaces inclinedwith respect to the vertical and having stepped lower cutting edges, theother teeth being interposed with respect to the rstnamed teeth andhaving substantially vertical advancing faces, said last-named teethlikewise having stepped lower cutting edges and extending to a diameterbeyond the outer diameter of the first-named teeth, the body beingprovided with ports for the delivery of lubricating mud directly to theadvancing faces of all of the teeth, there being a port for each of theteeth, with each port discharging downwardly into a region intermediatethe edges of the associated advancing face.

5. In a rotary earth-boring drill, a cutting head comprising a bodyprovided with at least four circumferentially spaced wing teeth, two ofthe wing teeth being disposed on opposite sides of the head and havingladvancing faces inclined with respect to the vertical, said teeth alsohaving at least two lower cutting edges stepped to cut on areas atdifferent diameters, the other wing teeth being interposed with respectto the rst-named teeth and having substantially vertical advancingfaces, said last-named teeth likewise having at least two lower cuttingedges stepped to cut on areas at different diameters and also havingouter substantially vertical rearning edges eX- tending to a diameterbeyond the outer diameter of the first-named teeth, the body beingprovided with downwardly-extending ports for delivering lubricating mudto the advancing faces of the teeth, there being a port for each tooth,with the discharge end of each port intermediate the edges of theassociated advancing face, the discharge end of each port beingsubstantially directly above the junction of the two areas to which thelower edges of the first-named teeth are adapted to out.

6. In a rotary earth-boring drill, a cutting head comprising a bodyprovided with at least four circumferentially spaced wing teeth, two ofthe wing teeth on opposite sides of the head having advancing facesinclined with respect to the vertical and having stepped lower cuttingedges, the other wing teeth being interposed with respect to theErst-.named teeth and having substantially vertical advancing faces,said lastnained teeth likewise having stepped lower cutting edges andalso having substantially vertical rearning edges extending to adiameter beyond the outer diameter of the rst-named teeth, the bodyhaving an opening therethrough for passage of a core, the outer contourof the body being tapered downwardly to form a substantiallyunobstructed annular lip surrounding the lower end of said opening, thelowermost cutting edges of the firstmamed teeth extending below said lipto form a core for passage through said opening.

7. In a rotary earth-boring drill, a cutting head comprising a bodyprovided with at least four circumferentially spaced teeth, two of theteeth being disposed on opposite sides of the head and having at leasttwo stepped lower cutting edges, the other teeth being interposed withrespect the first-named teeth, and having at least two stepped lowercutting edges, said last-mentioned teeth extending to a diameter beyondthe outer diameter of the rst-named teeth, the lowermost cutting edgesof all the teeth being substantially coincident with respect to a commonplane normal to the axis of rotation of the drill, the uppermost lowercutting edges of the first-named teeth being at a lower elevation thanthe uppermost lower cutting edges of the second-named teeth.

LEONARD S. COPELIN.

